package number;

public class Rand7Rand5 {

  public static int rand7() {
    while (true) {
        int num = 5 * rand5() + rand5();
        if (num < 21) {
            return num % 7;
        }
    }
}

public static int rand5() {
    return (int) (Math.random() * 100) % 5;
}

public static void main(String[] args) {
    /* Test: call rand7 many times and inspect the results. */
    int[] arr = new int[7];
    int test_size = 1000000;
    for(int k = 0; k < test_size; k++){
        arr[rand7()]++;
    }

    for (int i = 0; i < 7; i++) {
        double percent = 100.0 * arr[i] / test_size;
        System.out.println(i + " appeared " + percent + "% of the time.");
    }
}

}
